A substrate for suspension comprises a metallic substrate, an insulating layer formed on the metallic substrate, a conductor layer formed on the insulating layer, and a cover layer covering the conductor layer. The insulating layer and the cover layer are formed from different materials, whose coefficients of hygroscopic expansion are in the range between 3×10−6/% RH and 30×10−6/% RH. The difference between the coefficients of hygroscopic expansion of the two materials is 5×10−6/% RH or less.